September 16-19, 2008 Hamburg 2008 Olaf Scholten For the NuMoon collaboration KVI, Groningen.
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Transcript of September 16-19, 2008 Hamburg 2008 Olaf Scholten For the NuMoon collaboration KVI, Groningen.
September 16-19, 2008 Hamburg 2008
Physics of Cosmic raysSpectrum is power lawFlux ~ E-3 Non thermal spectrum!
There must be sources!
Where? What? End point?
This talk:Measurement at highest
E
(Area Moon = 2 107 km2)
F(E)
[ m
2 s
r s
GeV
] -1
E [eV ]
10-28
104
109 1021
← 3
2 o
rders
of
magnit
ude
← 12 orders of magnitude
← 1 [m-2 s-1]
1 [km-2 y-1] UHECR
E-2.7
September 16-19, 2008 Hamburg 2008
Cosmic ray or neutrino
100MHz Radio waves
Detection:
LOFAR
Principle of the measurement
107 km2
September 16-19, 2008 Hamburg 2008
Askaryan effect: Coherent Cherenkov emission
• Leading cloud of electrons, v c
Typical size of order 10cm
Coherent Čerenkov for ν 2-5 GHz
cos θc =1/n , θc=56o for ∞ shower length
• Length of shower, L few m
Important for angular spreading
~10 cm
~2 mCosmic ray or neutrino
shower
Wave front
nano second pulses
September 16-19, 2008 Hamburg 2008
Use Westerbork radio observatory
NuMoon Experiment @ WSRT
4 frequencies
September 16-19, 2008 Hamburg 2008Trigger: pulse in all four frequency bands
+ dedispersion
18 TB raw data per 6 hr slotTime Frequency
Excise RFI
Trigger
September 16-19, 2008 Hamburg 2008
Trigger Power Spectrum
Gaussian noise
Effect successive steps in analysis
September 16-19, 2008 Hamburg 2008
Prelimenary Results
Analysis of 20 h data
Data taking is continuing
NuMoon collaboration:
O.S., Stijn Buitink, Heino Falcke, Ben Stappers, Kalpana Singh, Richard Strom
September 16-19, 2008 Hamburg 2008
Future: LOFAR
SKA, 1 year,
LFB: 100-300 MHz
MFB: 300-500 MHzFrom: O.S., SKA Design Study report
LOFAR Core 1 month
E-LOFAR, 1 year